The latest device to blur the line between smartphones and tablets, the phone features the largest 1080p HD display ever on a smartphone, according to Sony.

A year ago, phone makers were pushing size boundaries with 5-inch screens, but 2013 has seen 6-inch-plus screens. One of the first was the 6.1-inch Huawei Ascend Mate, and that was followed by Samsung's 6.3-inch Galaxy Mega.

These large smartphones are getting very close to the size of tablets. The Nexus 7, the Amazon Kindle fire HD and other popular small tablets come with 7-inch screens.

In addition to a large screen, the Sony Xperia Z Ultra packs top-of-the-line hardware. The LTE phone features a powerful Qualcomm Snapdragon 800 2.2GHz quad-core processor and uses Android 4.2 Jelly Bean. It also features an 8-megapixel rear camera and 16 gigabytes of storage, all in a device that is just 0.26 inches thick.

And as with all of the latest Sony smartphones, the Xperia Z Ultra is described as waterproof and dust-proof. It can go nearly five feet underwater for a half hour.

Sony did not specify when the Xperia Z Ultra will come out in the U.S. It is scheduled to make its global launch some time in the next few months.